Class: Verneuil::Scope

Inherits:
Object
  • Object
show all
Defined in:
lib/verneuil/scope.rb

Overview

The execution scope for verneuil code. This maintains a link to the external context given when starting the process to be able to delegate method calls to user code.

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(context, local_vars = {}, parent = nil) ⇒ Scope

Returns a new instance of Scope.



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# File 'lib/verneuil/scope.rb', line 10

def initialize(context, local_vars={}, parent=nil)
  @local_vars = local_vars
  @context = context
  @parent = parent
end

Instance Attribute Details

#context ⇒ Object (readonly)

In Ruby, we also call this the ‘self’.



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# File 'lib/verneuil/scope.rb', line 8

def context
  @context
end

Instance Method Details

#child(local_vars = {}) ⇒ Object

Returns a nested scope that has access to the current scope in a Ruby 1.9 fashion.



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# File 'lib/verneuil/scope.rb', line 47

def child(local_vars={})
  self.class.new(context, local_vars, self)
end

#defined?(name) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/verneuil/scope.rb', line 38

def defined?(name)
  return 'local-variable' if lvar_exist?(name)
  return 'method' if context.respond_to?(name)
  nil
end

#inspect ⇒ Object 



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# File 'lib/verneuil/scope.rb', line 55

def inspect
  "scope(#{@local_vars.inspect[2..-2]})" + 
    (@parent ? "-> #{@parent.inspect}" : '')
end

#lvar_exist?(name) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/verneuil/scope.rb', line 16

def lvar_exist?(name)
  lvar_exist_locally?(name) || @parent && @parent.lvar_exist?(name)
end

#lvar_exist_locally?(name) ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/verneuil/scope.rb', line 19

def lvar_exist_locally?(name)
  @local_vars.has_key?(name)
end

#lvar_get(name) ⇒ Object 



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# File 'lib/verneuil/scope.rb', line 22

def lvar_get(name)
  unless lvar_exist_locally? name
    return @parent.lvar_get(name) if @parent
    
    raise Verneuil::NameError, "No such local variable #{name.inspect}."
  end

  @local_vars[name]
end

#lvar_set(name, value) ⇒ Object 



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# File 'lib/verneuil/scope.rb', line 31

def lvar_set(name, value)
  unless lvar_exist_locally? name
    return @parent.lvar_set(name, value) if @parent && @parent.lvar_exist?(name)
  end

  @local_vars[name] = value
end

#method_call(name, *args) ⇒ Object 



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# File 'lib/verneuil/scope.rb', line 51

def method_call(name, *args)
  context.send(name, *args)
end